A large and growing population of users is enjoying entertainment through the consumption of digital content, such as music, movies, images, electronic books, and so on. The users employ various electronic devices to consume such content. Among these electronic devices are electronic book (eBook) reader devices, cellular telephones, personal digital assistants (PDAs), portable media players, tablet computers, netbooks, and the like. As the quantity of available electronic media content continues to grow, along with increasing proliferation of devices to consume that media content, finding ways to enhance user experience continues to be a priority.
Electronic paper displays (EPDs), also referred to as electronic ink (e-ink) displays, are often used for eBook readers, because like paper, the image that they display is viewed using reflected light, rather than emitted light as is the case with a liquid crystal display (LCD) or light emitting diode LED display. As a result, EPDs provide a clear image in bright sunlight. Because the image on an EPD does not need to be constantly refreshed, very little electrical power is required for the display. Text remains readable once it has been initially rendered on the EPD, and electrical energy is consumed by the EPD only when the image that appears is changed so that a new image must be rendered.
For eBook devices, 16 gray levels for each pixel are sufficient to produce gray-scale graphic images and text. However, electrophoretic displays can include red, green, and blue (RGB) filters, with a different color filter overlaying each pixel of an electronic ink display, to produce a color EPD image. Unfortunately, the color filter reduces the intensity of reflected light so that the brightness of the color image rendered on the EPD is diminished, compared to a corresponding gray-scale image rendered on the display. To compensate, a white pixel can be included for each set of red, green, and blue pixels, producing an RGBW display with increased brightness. Although an RGBW electrophoretic EPD provides a brighter image, the resulting image will often have low contrast, low saturation, color fringing, and color banding in areas of color gradient.